The present invention relates generally to handling of cartons and, more particularly to an apparatus/method for feeding and turning cartons during transition between two conveyors.
It is well known to form paper board cartons or boxes on a forming machine including a plunger and die arrangement at a first station, fill the carton at a second station through its open top and then close and seal the carton as the cartons are being transported along a series of conveyors. For many years, the most successful approach to feeding of the cartons along the entire cartoning line, including for closing and sealing, was performed by conveyors in-line with lugs or flights that are mounted on chains and move the cartons forward by pushing along the rear edge. At various transition locations along the cartoning line, it was necessary to turn the carton about its vertical axis while continuing to feed the carton forward. Usually, this turning motion was through 90 degrees and was performed in one fashion or another with the help of the lugged chains. The overall manner in which such cartons were handled for in-line continuous feeding/turning is generally shown in the pioneer Baker U.S. Pat. No. 3,267,637, owned by the assignee of the present invention. In the case of the Charlotte type carton illustrated, the front or Charlotte flap is sealed first, and then after a turn of the carton through 90 degrees, the two side flaps are sealed.
Over the years prior to this key innovation, various attempts, some reasonably successful, had been made at performing the feeding/turning operation of the cartons in an intermittent or semi-automatic operation. In one such approach, two sections of the conveyor are simply situated at right angles to one another. After the first operation is performed, the carton comes to a stop at the juncture between the two conveyors, and the second conveyor then picks up the carton and the second operation is performed. Of course, it can be recognized that this type of approach is very slow and could not compete with the basic Baker '637 continuous approach since the carton must be stopped between the two operations. Furthermore, this arrangement is generally not desirable from the standpoint of conservation of floor space.
Accordingly, over the more recent years, the technology focuses on turning of cartons without stopping, or literally on the fly, as pioneered in the '637 patent. Several approaches that have been reasonably successful employ angled guide elements, such as a flexible brush type plow to retard one side of the carton. To provide an assist for the turning function, a continuously rotating finger is timed to push the leading edge of the carton around prior to entering the take away conveyor. One such approach is illustrated in the prior patent to Bryson, U.S. Pat. No. 4,476,972, also owned by the assignee of present application. While this approach provides for continuous, in-line feeding/turning, it still requires the use of lugs or flights on the bottom feed chains to successfully carry out the operation.
In more recent years, other efforts have been made to perform the turning operation utilizing lugless conveyors, that is conveyors without the lugs. These efforts still follow the basic concept pioneered in the '637 patent, mentioned above. An example is the Wallin U.S. Pat. No. 4,672,792 wherein a Charlotte type carton moves along an infeed conveyor, the carton is then turned through 90 degrees on a flat, lugless intermediate conveyor, and then the carton is transferred to a take away conveyor. This approach relies solely on one, or a plurality of side running belts to retard a leading corner. This causes the carton to laterally scoot around on the flat belt for turning. A particular drawback of this approach is the lack of control of the carton, and thus the limited speed at which it can successfully operate.
Another approach in the packaging field is illustrated in the Hemus U.S. Pat. No. 5,024,317. This approach is very similar to the Wallin approach, but instead of using a side running belt for the turning function, a bottom running chain with upstanding L-shaped lugs that must be raised to intercept each carton is used. The conveyor has roller segments that perform the forward feed function by engaging the bottom of the carton, which feeding action is thus necessarily unreliable, since the contact is only at widely spaced points. Again the speed, but also in this instance the accuracy, of the feeding and turning operation in this prior art approach suffers.
Accordingly, a need is identified for taking the next step up in development of carton feeding and turning systems. Of particular importance is a need for improving the speed, as well as efficiency and accuracy of the carton feeding/turning operation, while at the same time maintaining the simplicity afforded by a lugless operation. An improved system wherein the feeding and turning of successive cartons along the flow path is carried out by a novel arrangement of horizontal belts laterally spaced across the conveyor section to perform both the feeding and turning operations is contemplated. In conjunction with this arrangement, it is anticipated that the turning operation is assisted by retarding means along one side of the carton flow path.